PE-RT tubing for municipal water service is typically required to meet the requirements of AWWA C901-17 Polyethylene (PE) Pressure Pipe and Tubing, ¾ In. (19 mm) Through 3 In. (76 mm), for Water Service. AWWA C901-17 requires PE-RT tubing to have a material designation code of PE4710. PE-RT tubing meeting the requirements of ASTM F2769 and/or CSA B137.18 may also be approved for this application.
Since PEX and PE-RT tubing are both copper tube size (CTS) products, they utilize standard compression joint valves and fittings (when used with approved inserts), so they are easy and convenient to install. This includes brass valves and fittings made to AWWA C800 requirements, as well as polymer valves and fittings, when approved. Just as with HDPE pipes, inserts have negligible effect on pressure loss.
In addition, several types of metal and polymer fittings which are designed specifically for PEX and/or PE-RT tubing may be approved for water service and building supply line applications. This includes fittings produced to nationally accredited standards such as ASTM F1807, F1960, F2080, F2159, F3347, and F3348, as well as ASSE 1061 for push-fit fittings.
As stated in AWWA C904, "Each such fitting should be qualified before use by investigation and by tests when necessary to determine that the fitting is suitable and safe for the intended service." This includes specific approvals from fitting manufacturers for buried water service and building supply line applications.
Unlike buried metal pipes, plastic water service and building supply lines will not corrode or suffer mineral build-up, nor will they contribute dissolved metals into drinking water. Plastic water service and building supply lines must be certified to NSF/ANSI/CAN Std. 61 for drinking water safety.